Spark plug



A.' ROSENFELD.

SPARK PLUG. APPuc/Tlorruzn mw lo, 1920.

Patented Oct. 3, 1922.

Patented Oct. 3, 1922.

ARTUR RosNFnLnor s'r. Louis,` rlrrssotrru.`

"SPARK PLUG. j

Application mea May 1o, 1920.` seriai No. 380,265.

To all whom t may concern.'

Be it known that I, ARTHUR RosnNrELu, a citizen ofthe United States, residing at St. Louis, Missouri, have inventedV a certain new and useful Improvement in Spark Plugs, of which the following is a full, clear,

and exact description, such as will enable others skilled in the art to which it appertains to make and use thesame, reference being ahad to the accompanying drawings, forming part of this specification.

My invention relates to spark plugs such as are generally use dforproducing an electric spark for the ignition of the explosive charges in the combustion chambers of in"- ternal combustion engines, the principal obo ject of my invention being to generally im-V prove upon and simplify the construction of the existing types of spark plugs, and par` ticularly those forms ofplugs which are provided with intensifying spark gaps.

Further objects ofmy invention are, to provide a relatively simple andIeiicient spark plug that may be easily and cheaply produced, and the, construction being such .that the intensifying gapis under all conditions self-adjusting lso that after theparts of the plug have been properly assembled,` it will notbe necessary to make any adjustments to producev the intensifying gap between `the electrodes.

Further objects of my `invention are, to provide a spark plug that can be readily assembled ortaken apart; to provide one of the electrodes of the plug with a ball and socket joint which enables the lower end 4of said electrodeto automaticallyadjust itself upon the lower insulator, and with respect tothe electrode carried byfsaid lower insulator; and, further, toI provide a plug wherein the upper insulator, is very firmly secured in position withinvthe upper portion of theI body of the plug. j

With the foregoingv andjother objectsl in view, my invention consists in certainnovel features of construction and arrangement of partshereinafter more` fully described and claimed,l and illustrated inthe accompany-- ing drawings, intwhichj-xl` Y L p i Figure 1 is a vertical section takenthrough the centerof a spark plug of `my improved construction. i

Figure?l isa horizontal 4section taken approximately on the line 2-2 of Figurel. l,

`Figure 3 is an elevational view of the cap insulator that isarranged in the upper portion of the spark plug. l

Figure 4: is an enlarged vertical, section taken approximately on the :line 4-4 of Fi ure1. .j .l yigure 5 is a section similar to Figure 4 and showing aY modified form of the electrede or current, carrying memberthat is seated in the upper or cap insulator.

Referring by numerals to the accompany ing drawings y which illustrate a vpractical embodiment of my invention, 10 designates themain body portion of theplug which is shell of metal, the lower portion thereof be ingreduced in diameter and providedlwith an external thread 11 whereby the plug may be screwed intolthe wall of an internal co1nbustion engine. j 3 j j Tv e uppenportion of the wall of the shell `in the form of `a substantially cylindrical 10 `is internally threaded in order to receive Y' the externally threaded lower end of a metal bushing' 12. Thev `enlarged upper portion of the shell 10 kis provided with angular faces 13 adapted to receive a wrench or like tool wherebyl the plug may be screwed into the enginecylindergand the bushing 12 is provided `with angular faces 14- adapted to' receive a suitable tool Lwhereby said bushing is screwed into said shell. j

Formed withiirthe shell 10 between the Vlarger upper portion and relatively small lower portion is a horizontally disposed annular shoulder 15 and bearing thereupon is a suitable 'gasket 16, preferably of metal, or a combination of metal and` asbestos. Bearingdirectly on topof this gasket vis the un-` derside of a relatively'wide flange 17 that projects outwardly from the central portion ing on top of said `Oasket isthe beveled lower edge of the vwall o the bushingv 12. y l

The construction `just described, and particularly the arrangement of the gasketsl between the flange 17 of the core insulator and the shell 10and bushing 12 maintains the' coreinsulator in firm and substantial posiloo tion within said shell and provides fluid pressure tight joints between the assembled parts.

Extending axially through the core insulator 18 is an electrode 21, the upper end 22 thereof projecting a slight distance above the upper end of the body of said core insulator and the lower end of said electrode terminating a short distance below7 the skirt of said insulator. Secured to the lower end of the shell 10 is a substantially L-shaped electrode 23, the free end of which terminates adjacent to the lower end of the electrode 21.

Fitting snugly within the bushing 12 and projecting a short distance above the upper end thereof is a cap insulator 24 in the lowei` portion of which vis formed an upwardly projecting recess 25 and which latter, when the parts are properly assembled, receives the upper portion of the core insulator 18.

Formed in the outer face of the lower portion of this cap insulator and at diametrically disposed points are bayonet ljoint grooves 26 which are adapted to receive the inner ends of pins 27 that are seated in the bushing 12. Formed in the outer face of the lower portion of the cap insulator is a series of annular grooves 28 and before the cap insulator is inserted in the bushing, these grooves, as well as the bayonet grooves 26, are lilled with a suitable cement which, when dry and hard, very firmly secures the cap insulator within the bushing.

lVhen the cap insulator is inserted into the bushing and said insulator is turned so that the inner ends of the pins 27 occupy the ends of the horizontally disposed portions of the bayonet grooves it will be practically impossible for said cap insulator to become disengaged from the bushing even though the cement should become loose.

Formed through the upper portion of the cap insulator is an aperture 29 and seated therein is a short metal tubular member 30 that is provided on its lower end with an outwardly projecting flange 31, which latter bears against the bottom of recess 25.` The upper end of member 30 is externally thread# ed and screw-seated on this threaded portion is a nut 32 which, when tightened against the top of the cap insulator, very firmly anchors said member in said insulator.. Member 30 is internally threaded and passing therethrough .is a short threaded rod 33, the lower end of which is connected by a ball and socket joint 34 to an inverted cupshaped member 35 which latter is adapted to bear directly on top of the core insulator 18 around the projectingr upper end 22 of elec` trode 21.

Screwseated on the upper portion of' the threaded rod `33 is a lock nut 36 that is adapted to bear directly on top of nut 32 to lock the same against reverse movement, and screw-seated on that portion of the rod above the lock nut 36 is a binding nut 37 that is adapted to secure the terminal portion of the electric connection that leads to the spark plum rie extreme u per end of rod 33 is pro vided with angular faces 38v in order to be engaged by a wrench or like tool for the purpose of screwing said rod in either di rection through member 30.

Then the parts of my improved plug are assembled and the bushing 12 is screwed tightly into the shell 10, the beveled lower edge of the wall of said bushing bears directly on top of the gasket 2() and causes the flange 17 of the core insulator to bear with pressure against gasket 16, thereby firmly holding the core insulator in a central position within the shell and forming joints between the cooperating parts which will effectually prevent leakage of gas or fluid pressure through the lug.

lVhen the parts of t e plug are assembled, the threaded rod 33 is screwed through member 30 until the lower edge of the inverted cup-shaped member 35 bears on top of the core insulator, and thc space between the wall of said member 85 and the projecting upper end 22 of the electrode 21 forms an intensifying spark gap for the current in traveling through the plug must jump this gap with the result that a relatively large or fat spark is produced between the ends of the electrodes 21 and 23, and which spark is etective in igniting the explosive charge in the combustion chamber of the engine.

Inasmuch as the cup-shaped member is connected by a ball and socket joint to rod 33, said member will automatically adjust it self to any variation on theupper surface of the core insulator due to inaccuracies of manufacture or for any other cause and this arrangement provides for an intensifying spark gap that is fixed or of the same width under all conditions.

In Figure 5 I have shown a modified construction wherein the inverted cup-shaped member that encloses the upper end of the electrode carried by the cap insulator is normally under spring tension, such arrangement being effected by the use of a tubular member 38 that is seated in the center of the cap insulator and said member being connected-directly to the threaded rod 39 that projects upwardly through said cap insulator, Arranged to slide freely through the lower portion of the tubular member 38 is a pin 40, the lower end of which is connected by a ball and socket joint 41 to an inverted cup-shaped member 42 and positioned within the tubular member' 38 and bearing on top of pin 1.0 is a compression spring 43,

duced between the terminals of the elec 4 trodes that. are disposed within the combustion chamber of the engine, and as a result, a tiring spark of sufficient intensity is pro duced which will insure the ignition ofthe explosive charge. When the parts of the plug are properly assembled, the space within recess or chamber 25 is practically air-tight,

`and after the plug has been in operation for a short period of time, the greater portion of the nitrogen and oxygen within this air tight chamber will be consumed by the spark produced by the intensifying gap between the parts 22 and 35 and as a result of this absence of atmospheric resistance, the efficiency of the device in operation will be materially increased. A,

It will ,be readily understood that minor changes in the size, form and construction of the various parts of my improved spark plug can be made and substituted for those herein shown and described, without departing from the spirit of my invention, the

scope of which is set forth in the appended claims.

I claim as my invention:v jl. In a spark plug, a shell, an insulating core positioned therein, an electrode extending through said core, a cap insulator enclosing the upper portion of said insulating core, an electrode carried by said cap insulator and adapted to cooperate with the electrode carried by the insulating core to form an intensifying spark gap, a ballon the end of said cap electrode, and a cooperating socket member bearing against said core.

2. In a spark plug, a shell, an insulating cere positioned therein, an electrode extending through said core, a cap insulator enclosing the upper portion of said insulating core, a spring-pressed electrode carried by said cap insulator, and said last mentioned electrode being connected with said core by means of a ball and socket joint.

3; In a spark plug, a pair of insulators,v

electrodes carried by saidy insulators and one of which electrodes is provided with a ball and socket joint whereby ity is self-adjusting with respect to the opposite electrode and the insulator in which said opposite electrode is positioned. j

4. In a spark plug, a shell, an insulating -core positioned therein, an ,electrode carried by said core, a bushing removably positioned in the shell, an insulator carried by said bushing and partially enclosing the upper portion of the first mentioned insulator, `and an electrode carried bythe` insulator in said bushing, the lower end of said last mentioned electrode being adapted to' bear on the upper portion of the insulator carried by the shell, and the electrcdejthat is carried by the .insulator in saidfbushing being pro.- vided with a ball and socket joint.

5. In a spark plug, a bushing, an electrode carrying insulator positioned in Said bush` ing, and there being a bayonet joint between said insulator and bushing. y

6. In a spark plug, an electrode terminating in a ball, a socket member mounted on said ball and provided with an annular rim projecting away from said electrode, an insulator seated against said rim, and an elec.-

trode carried by said insulator and project-l ing' beyond same within the recess formed by saidrim.

7. In a spark plug, a bushing, an electrode carrying insulator positioned in said bushing, there being annular grooves formed in the outer face of said insulator, which grooves are adapted to receive cement for securing the insulator to said bushing, and there being a bayonet joint between said insulator and bushing. A i

8. In a spark plug, ashell, an insulating core positioned therein, an electrode extend ing through said core, a bushing removably positioned in said shell, a cap insulator carried byl said bushing, a currenty carrying member passing through said cap insulator, and a recessed member connected by a ball and socket joint to the lower end of `said current carrying member and which recessed member encloses the upper end of the electrode that is carried by the core insulator and is adjustably seated on said core insulaw tor by means of said oint.

9. In a spark plug, a pair of'insulators, electrodes carried by said insulators, and an inverted cup-shaped member adapted to partially enclose one end of one of said electrodes and self-adjusting about the latter by means of a ball and socket connection to the other of said electrodes.

10. In a spark plug, a pair of insulators, an electrode extending through one of said insulators, an electrode adjustably positioned in the other insulator, and said adjustable electrode being provided with a ball and socket joint whereby it is selfadjusting with respect to the opposite electrode and the insulator in which said opposite electrode is positioned.

11. In a spark plug, a pair of insulators,

. electrodes carried by said insulators, the ad- 12. In afspark plug, an insulator, and a trodes being provided with a ball and socket current carrying member adjustably seated joint whereby its end portion is self-adjustthereon. by means of' a ball and socket joint. ing with respect to the adjacent end portion 10 13. In a spark plug, a pair of current of the opposite electrode.

5 carrying members, the adjacent ends of In testimony whereof I hereunto alx my which are spaced apart to provide an intensignature this 8th day of May, 1920. sfying spark gap, and one of said elee-l ARTHUR ROSENFELD. 

